Nippon Telegraph and Telephone Corporation

Naruto Arai

Jun Kato

Ken Okamoto

A measurement individual difference correction system for measuring voltage to ground includes a cable comprising a conductor, a floor panel provided on a floor and comprising a conductor, an oscillation circuit connected between the cable and the floor panel, and configured to output a signal, a voltage-to-ground measurement device comprising an upper electrode and a lower electrode positioned apart from each other, and configured to measure voltage between the upper electrode and the lower electrode, and a computation device in communication with the voltage-to-ground measurement device, in which the computation device calculates combined impedance of electrostatic capacity between the user and the cable, impedance of the user, and electrostatic capacity between the user and the upper electrode, by using voltage of the signal output from the oscillation circuit and the voltage between the upper electrode and the lower electrode measured by the voltage-to-ground measurement device.

Measurement individual difference correction system in ground voltage measurement

A device includes a resonant voltage measurement unitconfigured to input a predetermined frequency signal to a circuit including a fixed capacitance formed between a ground and a lower electrode, a variable capacitance formed between an upper electrode that is disposed above the lower electrode and the ground or between the lower electrode and the upper electrode, and a resonance inductor to measure a resonant voltage that is dependent on a current flowing in the resonance inductor when the variable capacitance is changed to cause the circuit to resonate, a pre-correction voltage-to-ground measurement unitconfigured to measure a pre-correction voltage-to-ground that is a voltage between a measurement electrode, which is disposed at an equal height to the lower electrode and forms a capacitance-to-ground between the measurement electrode and the ground, and a measurement probe connected to a conductor, and a voltage-to-ground correction unitconfigured to use the fixed capacitance, the variable capacitance, and the resonant voltage to obtain the capacitance-to-ground and to calculate a voltage-to-ground obtained by correcting the pre-correction voltage-to-ground using the capacitance-to-ground.

Ground voltage measuring and method

To easily measure a voltage to ground of electromagnetic interference waves generated on a cable. A capacitance-to-ground measurement mechanismincludes a first electrodeand a second electrodepositioned at equal altitudes to be opposed to the earth, and a first voltage measurement deviceto measure a voltage generated in a first resistanceconnected between the first electrodeand the second electrodeby an output signal from an oscillation circuit. A voltage-to-ground measurement mechanismincludes a GND electrodepositioned at an altitude equal to that of the first electrodeand the second electrodeto be opposed to the earth, and a second voltage measurement deviceto measure a voltage generated in a second resistanceconnected between the GND electrodeand a probethat is brought into contact with a cable coreas a measurement target. A computation mechanismincludes a computation deviceto calculate a voltage to ground of electromagnetic interference waves generated on a cable based on data of respective voltages measured by the capacitance-to-ground measurement mechanismand the voltage-to-ground measurement mechanism

Capacitive voltage measurement device

A common-mode voltage measurement apparatus according to an embodiment includes a measurement electrode attached to a conductor capable of being brought into contact with a coated cable, a measurement circuit configured to measure a common-mode voltage generated in the cable, and a compensation circuit connected in series between the measurement electrode and the measurement circuit, the compensation circuit being configured to compensate for a parasitic capacitive component formed between the measurement electrode and the conductor.

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Tokyo, Japan

Naruto Arai